In order to meet the increasing demand for wireless data traffic since the commercialization of 4th generation (4G) communication systems, the development focus is on the 5th generation (5G) or pre-5G communication system. For this reason, the 5G or pre-5G communication system is called beyond 4G network communication system or post long-term evolution (LTE) system.
Consideration is being given to implementing the 5G communication system in millimeter wave (mmW) frequency bands (e.g., 60 GHz bands) to accomplish higher data rates. In order to increase the propagation distance by mitigating propagation loss in the 5G communication system, discussions are underway about various techniques such as beamforming, massive multiple-input multiple output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and large-scale antenna.
Also, in order to enhance network performance of the 5G communication system, developments are underway of various techniques such as evolved small cell, advanced small cell, cloud radio access network (RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation. Furthermore, the ongoing research includes the use of hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM), filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).
The 5G system will support more diverse services in comparison with the legacy 4G systems. Examples of representative services are enhanced mobile broad-band (eMBB), ultra-reliable and low latency communication (URLLC), massive machine type communication (mMTC), and evolved multimedia broadcast/multicast service (eMBMS). A system supporting the URLLC service may be called URLLC system, and a system supporting the eMBB service may be called eMBB system. The terms “service” and “system” may be interchangeably used.
Among these services, the URLLC service is newly considered for the 5G system, while not being considered for 4G systems, and has requirements of ultra-reliability (e.g., packet error rate of about 10-5) and low latency (e.g., about 0.5 msec). In order to meet such demanding requirements, the URLLC service may be provided with a transmission time interval (TTI) shorter than that of the eMBB service in consideration of various operation schemes.
Meanwhile, the Internet is evolving from a human-centric communication network in which information is generated and consumed by humans to the Internet of things (IoT) in which distributed things or components exchange and process information. The combination of the cloud server-based Big data processing technology and the IoT begets Internet of everything (IoE) technology. In order to secure the sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology required for implementing the IoT, recent research has focused on sensor network, machine-to-machine (M2M), and machine-type communication (MTC) technologies.
In the IoT environment, it is possible to provide an intelligent Internet Technology that is capable of collecting and analyzing data generated from connected things to create new values for human life. The IoT can be applied to various fields such as smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart appliance, and smart medical service through legacy information technology (IT) and convergence of various industries.
In line with the application of IoT technologies to various fields, communication operators and vendors are eager to develop various IoT-based applications and systems. Among many IoT solutions, the licensed band cellular IoT (CIoT) is coming into the spotlight. This is because the cellular system operating on the licensed frequency band is more reliable than the non-cellular system and, as a consequence, guarantees more reliable services. For CIoT, eMTC and GSM/EDGE radio access network (GERAN) CIoT are under discussion in the standardization process, which is largely affected by the needs of communication operators.
Advanced communication technologies make it possible to allow communications among all things as well as persons, and this feature is represented by IoT. For example, a user may carry different types of multiple electronic devices, which may connect to each other through cellular communication, short range communication, and sensing technology links for implementing functions for user convenience and accomplishing efficient inter-device control. Such electronic devices may be commonly called IoT devices. Another exemplary IoT service may be implemented in the meter reading service with measurement devices which read for electricity and water and deliver the read values through a network. Another exemplary IoT service may be implemented in such a way of installing IoT devices to monitor public places or remote areas for public safety such that the devices detect occurrence of a specific event and notify the progress of the event through a network. Still another exemplary IoT service may be implemented in such a way that home electric appliances equipped with a communication function are deployed to report their operation status and the user may make a device trigger to command the electric appliance to perform a specific operation.
An IoT device includes a cellular communication module such as an LTE module or a short-range communication module such as a Bluetooth, a wireless local area network (WLAN) or wireless fidelity (Wi-Fi) module, a Zigbee module, and a near field communication (NFC) module. An LTE terminal may be configured to operate on an LTE carrier frequency and/or an industrial, scientific, and medical (ISM) band.
There are various attempts to apply the IoT to the 5G communication system. For example, the sensor network, Machine to Machine (M2M), and Machine Type Communication (MTC) technologies are implemented by means of 5G communication technologies such as beamforming, MIMO, and array antenna. The application of the aforementioned cloud RAN as a big data processing technology is an example of convergence between the 5G and IoT technologies.
Throughout the specification of the present disclosure, CIoT denotes an IoT service over a cellular network. The cellular network means a mobile communication network such as a 2G network represented by GERAN, a 3G network represented by GPRS, and a 4G network represented by LTE. The CIoT service means a cellular service for supporting the IoT terminals or a service for transmitting small size data through the cellular network. The CIoT service may include Machine Type Communication (MTC) services. The cellular network is intended to include core networks and radio access networks.
In the present disclosure, SCEF is an abbreviation of service capability exposure function defined in the 3rd generation partnership project technical specification (3GPP TS) 23.628. Also, SCS/AS is an abbreviation of service capability server/application server supporting various SCEF-based services.